Tier One supplier Continental is working on Road Departure Protection systems that aim to prevent unintended road departures. The systems will automatically steer a vehicle back into its lane when it begins to inadvertently leave the road or cross the center line into oncoming traffic.
According to the Federal Highway Administration, approximately 55 percent of traffic fatalities in the U.S. involve a vehicle crossing the roadway or center line. In Germany, 60 percent of fatal road accidents and 25 percent of non-fatal road accidents occur on rural roads, according to the German Federal Statistical Office.
Continental said the systems differ from Lane Keeping and Lane Departure Warning systems in that they specifically monitor the outside boundaries of the roadway and act with more authority to keep the vehicle within its intended space.
Road Departure Protection systems go beyond the lateral ADAS (Advanced Driver Assistance Systems) by active road keeping in emergency situations before reaching the physical limits of vehicle dynamics. Leveraging environment perception, such as road edge detection or road course preview, the systems are designed to intervene actively when a vehicle leaves the roadway unintentionally.
A Virtual Guard Rail
“The system serves as a virtual guard rail, protecting the vehicle and its occupants from accidentally leaving the road; ultimately minimizing the risk of a potentially fatal accident due to driver error, distractions or drowsiness,” said Steffen Linkenbach, Head of Systems and Technology for the Chassis & Safety Division, Continental North America.
“The Road Departure Protection system enhances our driver assistance portfolio of products by adding an intuitive solution that goes beyond the warning phase by automatically steering the vehicle back into its lane while alerting the driver of the potentially dangerous situation.”
Automatically Steering a Vehicle Back into its Lane
The base system, which uses a forward looking mono camera to detect roadway boundaries, monitors the driver’s steering angle and vehicle path through existing Electronic Stability Control (ESC) sensors and also uses chassis motion sensors to identify if the vehicle is crossing the road boundary. It then uses the existing ESC system to apply individual wheel brakes to automatically steer the vehicle back on the road while simultaneously warning the driver and reducing the speed of the vehicle.
Active intervention is signaled when the vehicle senses it is departing the road. The system’s performance can be enhanced by road edge rumble strips, creating an opportunity for a combined vehicle plus infrastructure solution.
The system includes a driver intention recognition feature in the event that the driver intends to leave the road.
Continental is also working on an enhanced Road Departure system that uses a stereo camera and a long-range radar for improved detection of roadway boundaries, particularly for country roads in Europe.
The long-range radar and the stereo camera allow the generation of an occupancy map with information about the roadway within the vehicle’s field of view. Further confirmation of road departure and potential collisions is based on the map. The goal is to detect road boundaries even when lane markings are missing. Coordinated brake and steering intervention increase the efficiency of this system.
The further integration of road map and onboard GPS data also support an advanced preview ESC feature that detects the course of the road before entering a curve. Based on the predicted road curvature, the driver is supported in situations where the driving dynamics are critical; for example with inappropriate speed during curve driving on a country road or tight curves, to keep the vehicle within the physical limits of the road.
“With this cascaded approach, we are developing an advanced system function designed to address a significant proportion of traffic accidents and fatalities worldwide,” said Alfred Eckert, Head of Advanced Engineering within Continental’s Chassis & Safety Division. “Both systems have the potential to promote increased vehicle and driving safety and contribute to Continental’s Vision Zero, the goal of achieving zero traffic accidents.”